The issue is when client try to extract more than 250 ISIN, they get an empty answer from the server. Please note that if client use 10 isins, client can extract with API perfectly, if client repeat those isin 100 times (so 1000 total isin requested) client get an empty answer, so the isins are not the problem.
The problem is not with Datascope, client can pull the data they need on GUI. They need to make the API works.
In relation to the source, it is not an * repeated but is a None (empty) value repeated (*) for the length of the isin list. If client run the API pull script with 10 isin it works, if the list of isin is those 10 isins repeated 100 times it give me back an empty answer. So the problem is not related to the isins.
Please see attached the function to import the data.